After shimmying her famous assets for ministers, ambassadors and executives at a resort town in the Muslim country, J.Lo slipped out of a skimpy dress into a traditional Turkmen white gown to sing a Marilyn-JFK-esque “Happy birthday, Mr. President” to the tyrant.

“It was my pleasure, and we wish you the very, very happiest birthday,” Lopez, 43, cooed on stage next to stars from Russia, Ukraine, Turkey and China.

Human Rights Watch has called Turkmenistan’s government “among the most repressive in the world.”

“Unknown numbers of people languish in the country’s notoriously abusive prisons on what appear to be politically motivated charges,” the nongovernmental organization charged in April.

Yesterday, Lopez’s rep said she regrets feting the leader, who’s been denounced for banning citizens from leaving the country, imprisoning and torturing people who openly criticize the government and detaining and censuring journalists.

Her spokesman, Mark Young, stressed that the event was not political or government sponsored.

“Had there been knowledge of human-rights issues of any kind, Jennifer would not have attended,” Young said in a statement.

The concert was organized by the Chinese state-owned oil and natural-gas company China National Petroleum Corp. as a corporate event for executives in Turkmenistan, a country located in Central Asia that was once part of the Soviet bloc.

“The China National Petroleum Corporation made a last-minute ‘birthday greeting’ request prior to Jennifer taking the stage. This was not stipulated in her contract, but she graciously obliged,” her rep said.

Taylor likely didn’t get a response — because Twitter is banned there.

“Jenny from the Block” may have been the first major US celebrity to visit the country, but it’s not her first time performing for top dollar in former Soviet countries. Lopez commanded $1.4 million in 2006 for performing at oligarch Telman Ismailov’s birthday in Moscow and $1 million in 2011 for singing at the wedding of the son of oil tycoon Azam Aslanov in Uzbekistan.

She’s also not the first celebrity to tangle with one of the world’s tyrants for a generous fee. Beyoncé, Mariah Carey, and 50 Cent were criticized for raking in up to $1 million to perform at a party for Libyan dictator Moammar Khadafy.